1. Field of the Invention
The present invention relates to a substrate transfer apparatus and a substrate transfer method, particularly to a substrate transfer apparatus and a substrate transfer method used for transferring an electronic substrate requiring high cleanliness such as a semiconductor wafer or a liquid crystal substrate between a substrate transfer container and a substrate processing apparatus.
2. Description of the Related Art
There is carried out fabrication of an electronic apparatus using an electronic substrate (hereinafter, described as substrate) such as a semiconductor wafer, a liquid crystal substrate for a display apparatus or a magnetic disk at inside of a dustless clean room. Meanwhile, when a substrate is transferred among respective substrate processing apparatus, the transfer operation is carried out in a state in which a substrate held in a cassette is contained in a portable hermetically-closable locally cleaned container (that is, substrate transfer container). Thereby, a substrate can be transferred without exposing the substrate to dust and dirt in the atmosphere at inside and outside of a clean room. Such a substrate transfer container is on sale under a commercial name of SMIF (Standard Mechanical Interface) pod (Assist Technology Co., Ltd.) and is constituted to mechanically connect to respective substrate processing apparatus as disclosed in Japanese Patent Publication No. 46694/1995 and Japanese Patent Laid-Open No. 46011/1996.
In the meantime, in fabrication of a high added-value and highly integrated device in recent years, molecule adsorption contamination at a surface of a substrate effects adverse influence on a device/process characteristic. Therefore, when a substrate requesting particularly high cleanliness such as a semiconductor wafer is transferred, inside of a substrate transfer container contained with the substrate is replaced by inert gas such as argon (Ar) or nitrogen gas (N2) (hereinafter, referred to as inert gas) to thereby prevent molecule adsorption contamination of organic substance, boron or phosphor to the substrate and formation of natural oxide film on the surface of the substrate.
Further, when only inside of a substrate transfer container is replaced by inert gas, during a time period until a substrate is transferred from a substrate processing apparatus to inside of the substrate transfer container (vice versa), the surface of the substrate is exposed to the atmosphere at inside of a clean room and accordingly, formation of natural oxide film on the surface of the substrate cannot be prevented. Therefore, there have been proposed mechanical interface apparatus as disclosed in Japanese Patent Laid-Open No. 221319/1996 and Japanese Patent Laid-Open No. 139410/1997. The mechanical interface apparatus is constituted such that in a state in which with respect to a substrate processing apparatus integrated with a substrate transfer unit (hereinafter, described as transfer unit) which serves also as a container opening/closing unit, inside of the transfer unit and inside of the substrate transfer container are replaced by gas, these are communicated with each other and transfer of a substrate is carried out.
However, an object of such a mechanical interface apparatus is a substrate processing apparatus previously integrated with a transfer unit. Therefore, in a normal substrate processing apparatus which is not integrated with the transfer unit, a substrate cannot be transferred between the substrate processing apparatus and a substrate transfer container while preventing formation of natural oxide film at the surface of the substrate. In order to carry out such substrate transfer operation to a substrate processing apparatus which is not integrated with a transfer unit, it is necessary to connect the substrate transfer container to the substrate transfer apparatus and the substrate transfer apparatus to the substrate processing apparatus while maintaining an air tight state against outside air. However, the conventional substrate transfer apparatus is not constructed by a constitution assuming such connection and accordingly, the substrate cannot be transferred from the substrate transfer container to the substrate processing apparatus (vice versa) without exposing the substrate to the atmosphere.
Hence, it is an object of the present invention to provide a substrate transfer apparatus capable of forming a hermetically-closed space integrated between a normal substrate processing apparatus and a substrate transfer container and a substrate transfer method capable of transferring a substrate between the substrate transfer container and the substrate processing apparatus without contaminating the substrate by adsorption of gas molecules in the atmosphere.
In order to achieve such an object, according to an aspect of the present invention, there is provided a substrate transfer apparatus used for transferring a substrate between a substrate transfer container and a substrate processing apparatus, the substrate transfer apparatus comprising a main body in a box-like shape contained with the substrate, a first opening provided at the main body and connected to a substrate transfer port of the substrate transfer container while maintaining an air tight state against outside air, a second opening provided at the main body and connected to a substrate transfer port of the substrate processing apparatus while maintaining the air tight state against outside air, an exhaust pipe connected to the main body, an opening/closing mechanism for opening and closing a lid provided at the substrate transfer port in a state in which the first opening and the substrate transfer port of the substrate transfer container are connected, and a transfer mechanism installed at inside of the main body for transferring the substrate.
According to such a substrate transfer apparatus, by connecting the second opening provided at the main body and the substrate transfer port of the substrate processing apparatus, the main body and the substrate processing apparatus are communicated with each other and the substrate transfer apparatus is subsequently attached to the substrate processing apparatus. Further, by the first opening and the second opening provided at the main body, the main body is communicated with the substrate transfer container and the substrate processing apparatus while maintaining the air tight state against outside air and accordingly, the substrate is transferred between the substrate transfer container and the substrate processing apparatus via the main body without exposing the substrate to outside air. Further, gas in the main body is exhausted from the exhaust pipe and accordingly, inside of the main body is maintained in an inert atmosphere.
Further, according to another aspect of the present invention, there is provided a substrate transfer method for transferring a substrate between a substrate transfer container and a substrate processing apparatus, the substrate transfer method comprising a step of communicating the substrate transfer container and the substrate transfer apparatus insides of which are maintained in an inert atmosphere while maintaining an air tight state against outside air and transferring the substrate between the substrate transfer container and the substrate transfer apparatus by a substrate transfer mechanism provided at inside of the substrate transfer apparatus, and a step of communicating the substrate transfer apparatus and the substrate processing apparatus the insides of which are maintained in the inert atmosphere while maintaining the air tight state against outside air and transferring the substrate between the substrate transfer apparatus and the substrate processing apparatus by the substrate transfer mechanism.
According to the substrate transfer method having such a constitution, the substrate can be transferred while maintaining the substrate in the inert atmosphere between the substrate transfer container and the substrate transfer apparatus and between the substrate transfer apparatus and the substrate processing apparatus.